* Reject union initialization with more than one reset value.
* Replace the reset value specified in the class definition with
the one provided during initalization instead of merging.
* Annotations like `s: unsigned(4) = 1` are recognized and
the assigned value is used as the reset value for the implicitly
created `Signal`.
* Base classes inheriting from `Struct` and `Union` without
specifying a layout are recognized.
* Classes that both inherit from a base class with a layout and
specify a layout are rejected.
Mutability of Field isn't specified by the RFC and can cause issues
if the objects stored in Layout subclasses are mutated. There isn't
any reason to do that (the subclasses themselves are mutable and
handle that correctly), so disallow it.
These operators are ignored when they are encountered on LHS, as
the signedness of the assignment target does not matter in Amaranth.
.as_signed() appears on LHS of assigns to signed aggregate fields.
Using floats to represent simulation time internally isn't ideal
instead use 1ps internal units while continuing to use a floating
point based interface for compatibility.
Fixes#535.
A check that rejects very large wires already exists in back.rtlil
because they cause performance and correctness issues with Verilog
tooling. Similar performance issues exist with the Python simulator.
This commit also adjusts back.rtlil to use the OverflowError
exception, same as in sim._pyrtl.
Fixes#588.
Avoid calling `__getattr__("_ValueCastable__lowered_to")` when
a ValueCastable has custom `__getattr__` implementation; this avoids
the need for downstream code to be aware of this implementataion
detail.
This was an especially insidious bug because the minus character is
valid in case values but has a completely different meaning (wildcard
rather than sign).
Fixes#559.
Commit abbebf8e used __getattr__ to proxy Value methods called on
Record. However, that did not proxy operators like __add__ because
Python looks up the special operator methods directly on the class
and does not run __getattr__ if they are missing.
Instead of using __getattr__, explicitly enumerate and wrap every
Value method that should be proxied. This also ensures backwards
compatibility if more methods are added to Value later.
Fixes#533.
